Best player I've seen in a Bolton shirt is Youri Djorkaeff.
Best performance by a Bolton player is a bit trickier (Tony Caldwell's five goals against Walsall, Aiden Davison's one-man show at Tranmere in the Anglo-Italian, Simon Charlton having Henry in his pocket at home to Arsenal), but I'd plump for John McGinlay in the 2-1 win at Stoke in the 100 goals season. He was outstanding up front on his own after Nathan Blake got sent off for standing near somebody.
As for the best individual display against us, the likes of David Lee, Robbie Fowler and Bob Taylor were constant thorns in our side, but none of them could match the majesty of Bradford's Wayne Jacobs.